Packaging container

ABSTRACT

A packaging container for a food product includes a tray ( 2 ) for receiving a food product, the tray including a base ( 4 ) and a peripheral wall ( 6 ), and a film lid ( 8 ) for sealed attachment to an upper edge of the peripheral wall to seal a food product ( 10 ) within the container. The film lid ( 8 ) includes a lower film layer ( 12 ) for sealed attachment to the upper edge of the peripheral wall ( 6 ) and an upper film layer ( 14 ) that is peelably attached to the lower film layer ( 12 ) so that it can be separated by peeling from the lower film layer. The upper film layer ( 14 ) carries at least one printed layer ( 20 ).

The present invention relates to a packaging container for a food product, a packaged food product, and a laminated film material for sealing a packaging container for a food product.

Pre-prepared food products such as chilled or frozen ready meals and ambient foods are often packaged in containers in which they can be heated to a serving temperature in a conventional oven or a microwave oven. Typically, the packaging container includes a tray that is made of a moulded plastics material for example crystalline polyethylene terephthalate (CPET) or polypropylene (PP), or of aluminum foil, and a film lid that is sealed to the tray. The lid is usually made of a transparent plastics film such as polyester (PET) or polypropylene.

Usually the film lid is left attached to the tray during heating to protect the food against discolouring and/or drying out, but it is punctured to allow steam to escape without building up excess pressure. The lid is unprinted to avoid the risk of ink migrating to the food. After heating, the film lid is removed and the food is served.

The packaging container is often delivered in a cardboard carton or box, which encloses the filled tray. The carton generally carries printed information, which may include for example a photograph of the product, the name of the product and of the manufacturer, trade marks, product codes for example in the form of bar codes, the weight of the product, nutritional information, a list of ingredients and cooking or preparation instructions. The carton therefore carries a lot of essential information about the product. It also helps to protect the tray and lid from damage during transportation and storage, and protects the food product from exposure to light. The carton is removed prior to heating the product.

In some cases, the cardboard carton is replaced by a simple cardboard sleeve that is wrapped around the tray, leaving its ends exposed. The sleeve serves the same purpose as the carton, carrying the essential information about the product and protecting the tray and the film lid from damage. The sleeve also protects the food product from exposure to light. Less material is required to produce the sleeve, thus providing cost savings and reducing the packaging weight as compared to a carton-packaged container.

It is an object of the present invention to provide an improved packaging container for food products, and an improved packaged food product.

According to one aspect of the present invention there is provided a packaging container for a food product, the packaging container comprising a tray for receiving a food product, the tray having a base and a peripheral wall, and a film lid for sealed attachment to an upper edge of the peripheral wall to seal a food product within the container, wherein the film lid comprises a laminated film material that includes a lower film layer made of a first plastics material for sealed attachment to the upper edge of the peripheral wall and an upper film layer made of a second plastics material that is attached by a peelable layer to the lower film layer so that it can be separated by peeling from the lower film layer, said upper film layer carrying at least one printed layer.

The upper film layer can carry in the printed layer all essential product information. It also helps to protect the food product from exposure to light. However, it can be removed by peeling prior to heating a product, leaving only the lower film layer attached to the tray. The lower film layer can then be punctured (if required) and the food product can be heated in the usual way. Removing the upper film layer ensures that the printed information is available to the user during heating. The upper film layer also helps to strengthen the film lid and protect it from damage during transportation and storage.

By providing all the printed information on the upper film layer, the previously required cardboard sleeve can be omitted, leading to a saving in cost and in the packaging weight.

Typically, the packing cost will be reduced by approximately 12% and the packaging weight by approximately 8 g per unit.

Advantageously, the peelable layer comprises a pressure sensitive adhesive. This adhesive should be formulated to meet Regulation (EC) 1935/2004 and Directive 2007/19/EC; it should also meet EC Plastic Directive 2011/10/EC covering articles intended to come into contact with food.

The adhesive is preferably formulated to create a bond at an application weight of 1.6 g/m² to 2.5 g/m² when the adhesive layer covers 100% of the film area. The weight of the adhesive layer can be altered in this range to weaken and/or strengthen the bond as required.

Alternatively, any other attachment process that allows the upper film layer to be separated by peeling from the lower film layer may be used. For example, the upper film layer may be attached to the lower film layer by peelable layer of a co-extruded polymer material.

Advantageously, the peelable layer is attached more strongly to the upper film layer than to the lower film layer, so that it is removed entirely from the lower film layer when the upper film layer is peeled away. This ensures that there is no possibility of material from the peelable layer migrating into the food product during heating. The peelable layer preferably has a bond strength with the lower film layer in the range 20-90 g per 25 mm width, more preferably approximately 30 g per 25 mm width. The bond strength is tested using a peel test that involves cutting a 25 mm wide strip of the laminated film and separating the film layers at one end of the strip, then measuring the force needed to pull the laminations apart. Most conventional adhesives typically have a bond strength in the range 650 g to 850 g per 25 mm width. The peelable layer of the present invention therefore has a very low bond strength, which allows the upper film layer to be peeled manually from the container by a customer to reveal cooking and nutritional information.

The lower film layer is preferably made of a PET homopolymer material. Preferably, the lower film layer includes an upper surface layer comprising a heat sealable copolymer material that allows easy peeling of the upper film layer. The lower film layer is preferably heat sealed to the upper edge of the peripheral wall. A lower surface of the lower film layer is preferably corona treated so that it forms a strong bond with the wall.

The lower film layer preferably has good barrier properties, which are essential for food products that are intended to be kept in ambient and chilled environments, with a water transmission rate of no more than approximately 20 g/m² per day and an oxygen transmission rate of no more than 60 cm³/m² per day.

Advantageously, the upper film layer is made of a polyester material. Preferably, a lower surface of the upper film layer is acrylic treated to ensure strong adhesion to the peelable layer. The upper film layer preferably has a thickness in the range 20-30 μm, more preferably approximately 23 μm. This ensures that the upper film layer does not curl when peeled from the lower film layer.

The laminated film material preferably has freezable properties so that it can be stored at a temperature of −45 C. without deterioration.

Advantageously, the upper film layer carries a first printed layer that can be viewed from a first side of the upper film layer and a second printed layer that can be viewed from a second side of the upper film layer. Thus, the upper side of the upper film layer may carry a photograph of the product, the product name and the manufacturer's name and trade mark, whereas the lower side of the upper film layer, which is only visible when the film is peeled away from the lower film layer, may include nutritional information and cooking or preparation instructions. By providing two printed layers the amount of information that can be carried by the upper film layer can be doubled.

In one embodiment, the first printed layer is printed on the first side of the upper film layer and the second printed layer is printed on the second side of the upper film layer. Both sides of the upper film layer therefore carry printed information.

In an alternative embodiment, the upper film layer is transparent and the first and second printed layers are printed on the same side of the upper film layer, whereby one of the printed layers can be viewed through the transparent film from a first side of the upper film layer, and the other printed layer can be viewed from the second side of the upper film layer. Preferably one of the printed layers is over-printed with the other printed layer.

In this embodiment, both printed layers are provided on the same side of the film but the first printed layer is over-printed with the second printed layer. Therefore, the first printed layer can be seen through the transparent film whereas the second printed layer can be seen by turning the film over to reveal the reverse side. The printed side of the upper film layer can be either the upper side or the lower side of the film.

Advantageously, at least one of the printed layers is substantially opaque, to protect the food product from exposure to light.

Advantageously, the lower film layer is transparent and preferably unprinted, allowing the food product to be seen before heating.

The lower film layer is preferably made of a heat resistant polyester material.

Advantageously, the tray is made of a plastics material, preferably a heat resistant plastic material such as a CPET material or a polypropylene material. Alternatively it may be made of any other suitable material, for example aluminum foil.

According to another aspect of the invention there is provided a packaged food product comprising a packaging container according to any one of the preceding statements of invention and a food product sealed within the container.

The food product may be a pre-prepared food product, preferably a chilled or frozen food product or an ambient food product, which is intended to be heated to a serving temperature in the packaging container.

According to another aspect of the invention there is provided a laminated film material for sealing a packaging container for a food product, wherein the laminated film material includes a lower film layer made of a first plastics material for sealed attachment to the packaging container and an upper film layer made of a second plastics material that is attached to the lower film layer by a peelable layer so that it can be separated by peeling from the lower film layer, said upper film layer carrying at least one printed layer.

In a preferred embodiment, the plastics films making up the upper and lower layers of the laminated film material are selected and treated to ensure the construction works in the following way: the upper layer when peeled carries with it all the pressure sensitive adhesive so that no adhesive is left on the lower film layer. This is achieved by using an acrylic coated material. For this to be suitable to work in a manufacturing environment, the adhesive covers 100% of the film area. In addition, the upper film layer has a thickness of approximately 23 micron to ensure the film does not curl back on itself when peeling, which would make reading the nutritional and cooking instructions difficult. The lower film layer is also a specially treated film, one side being corona treated to give it extra bonding properties to the base tray so that it doesn't come away when the upper layer is peeled, and the other side of this base layer film is treated with a copolymer to allow the peelable layer to stick to it. The lower film layer is preferably self-venting when heated in a microwave or conventional oven.

Preferably, the thickness of the upper film layer is approximately 23 micron and the thickness of the lower film layer is approximately 25 micron, these thicknesses ensuring functionality of the construction.

Even with these film properties the adhesive which covers 100% must have easy peel characteristics whilst still maintaining a bond at an application weight of approximately 1.6 g/m² to 2.5 g/m².

The film of the present invention does not require any perforations or laser cutting to generate the required peelability, which is achieved purely by the selected combination of films and adhesive that has an extremely low bond strength to allow manual peeling.

Various embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, wherein:

FIG. 1 is an isometric view of a packing container for a food product comprising a tray with a film lid;

FIG. 2 is a top plan view of a packing container having a film lid comprising upper and lower film layers;

FIG. 3 is a sectional side view of a film lid;

FIG. 4 is a sectional side view of a lower film layer;

FIG. 5 is a sectional side view of an upper film layer;

FIG. 6 is a sectional side view of the upper film layer, showing the positions of two printed layers according to a first embodiment of the invention, and

FIG. 7 is a sectional side view of the upper film layer, showing the positions of two printed layers according to a second embodiment of the invention.

As shown in FIGS. 1 and 2, the packaging container 1 includes a tray 2 having a base 4 and a peripheral wall 6. A film lid 8 is sealed to the upper edge of the peripheral wall 6 to seal a food product 10 within the container 1.

As shown more clearly in FIG. 3, the film lid 8 has a laminated structure comprising a lower film layer 12 that is attached (for example by heat-sealing) to the upper edge of the peripheral wall 6, and an upper film layer 14 that is peelably attached to the lower film layer 12, for example by a peelable layer 16 of peelable adhesive that covers substantially 100% of the film area. Optionally, the peelable layer 16 may be omitted in one corner of the film lid so that the unadhered corner of the upper film layer 14 provides a tab 18 that can be grasped, allowing the upper film layer 14 to be peeled easily from the lower film layer 12.

As shown in FIG. 4, the lower film layer 12 may for example be a co-extruded film comprising a core layer 20 made of a PET homopolymer material, has an upper surface layer 22 comprising a heat sealable copolymer material for low peel strength, and a lower surface layer 24 that is corona treated to allow it to be heat sealed strongly to the upper edge of the peripheral wall 6. A suitable material is for example the Easy Peel 10.63CT, 25my thermosealable PET film sold by Transparent Paper Ltd of Zurich. The lower film layer 12 preferably has a thickness in the range 20-30 μm, more preferably approximately 25 μm.

As shown in FIG. 5, the upper film layer 14 may be made for example be a co-extruded film comprising a core layer 26 of a polyester material with conventional upper and lower surface layers 28, 30, wherein the lower surface layer 30 has an acrylic surface treatment 32 for improved adhesion of solvent-based inks and adhesives. The upper film layer 14 preferably has a thickness in the range 20-30 μm, more preferably approximately 23 μm. A suitable material is for example the Sarafil Polyplex (®) type S42 23my polyester film sold by Transparent Paper Ltd of Zurich.

The upper film layer 14 is printed with at least one printed layer that carries essential information about the food product 10. Preferably, the upper film layer 14 is printed with two printed layers carrying information about the food product 10.

In a first embodiment as shown in FIG. 6, the upper film layer 14 carries a first printed layer 34 on the upper side of the upper film layer 14, and a second printed layer 36 on the lower side of the upper film layer. The first printed layer 34 can therefore be seen on the upper side of the upper film layer and the second printed layer 36 can be seen on the lower side of the upper film layer. The second printed layer 36 cannot be seen until the upper film layer 14 is peeled away from the lower film layer 12. Typically, the upper printed layer 34 will include printed information such as a photograph of the product, the name of the product, the name and trade mark of the manufacturer and the weight of the product, whereas the lower printed layer 36 will carry printed information such as nutritional information about the food product and cooking or preparation instructions. The upper film layer 14 has a construction to ensure that it does not curl when peeled from the lower film layer 12, as this would make it difficult to read the printed information.

In a second embodiment shown in FIG. 7, the upper and lower printed layers 34,36 are both printed on the lower side of the upper film layer 14. More specifically, the upper printed layer 34 is printed on the lower side of the upper film layer 14, and the upper printed layer 34 is then overprinted with the lower printed layer 36. The upper printed layer 34 can be viewed through the transparent film of the upper film layer 14 and the lower printed layer 36 can be seen when the upper film layer 14 is peeled away from the lower film layer 12.

The arrangement shown in FIG. 7 can of course be reversed: that is to say, the upper and lower printed layers 34, 36 can instead be printed onto the upper side of the upper film layer 14.

In order to prepare the food product for serving, the upper film layer 14 is peeled away together with the peelable layer 16 to expose the transparent lower film layer 12. Normally, this lower film layer 12 will then be punctured to allow steam to vent from the container during heating. Alternatively, the lower film layer 12 may be self-venting or may be provided with one or more pre-formed vents which open when the upper film layer 14 is removed, or with a steam pressure valve. However, as a safety precaution it may still be advisable to puncture the lower film layer 12. The food product is then heated by placing the tray with the still attached lower film layer 12 in either a conventional oven or a microwave oven, and heating for an appropriate time. After heating has been completed, the lower film layer 12 is either peeled or cut away, allowing the food product 10 to be served.

The lower and upper film layers 12, 14 may be made of any suitable plastics material, for example a polyester material or a polypropylene material, or any suitable alternative, providing that they are of sufficient thickness as described above. However, at least the lower film layer must be made of a heat-resistant plastics material that can tolerate a temperature of about 130-210 C., and which is preferably transparent with a low haze value for example of no more than about 7%, allowing the food to be viewed before cooking. Preferably, the laminated film lid 8 has sufficient strength to support a weight of at least 3.5 kg, so that a number of similar filled containers can be stacked in a retail display cabinet.

The plastic film material forming the film lid 8 is preferably supplied to the food manufacturing/packaging company in either reel or sheet form as a single laminated film comprising the heat-resistant lower film layer 12, the peelable layer 16 and the printed upper film layer 14. The film material is then applied to the filled trays using a conventional sealing process, for example by heat sealing or ultrasonic welding. However, it is possible to supply the upper and lower film layers separately and laminate the two film layers 12, 14 and the peelable layer 16 together either prior to, during or after sealing the film to the filled tray.

The tray 2 is typically made of a plastics material, preferably a CPET material or a polypropylene material. Alternatively, it may be made of aluminum foil.

Various modifications of the invention are of course possible. For example, the tray 2 may have any suitable shape, such as square, rectangular, circular or an irregular shape. It may also be divided into separate compartments for different food products.

The peelable layer 16 of adhesive between the upper and lower film layers 12, 14 may be replaced by a co-extruded layer of a peelable polymer material, providing that the laminated film material has the required peeling characteristics.

The laminated film lid 8 may optionally include a third film layer, so that it comprises two lower layers of a transparent film material and an upper printed film layer, for use in sterilisation (retort) applications. In this application the top two layers of film are laminated together using a retort adhesive and these film layers are subsequently laminated to the base layer using a suitable pressure sensitive adhesive or other peelable layer.

The food product may be a chilled or frozen food product, or an ambient food product, which is intended to be heated to a serving temperature in the packaging container. 

1-24. (canceled)
 25. A packaging container for a food product, the packaging container being configured to allow heating of the food product in the packaging container and comprising a tray for receiving a food product, the tray having a base and a peripheral wall, and a film lid for sealed attachment to an upper edge of the peripheral wall to seal a food product within the container, wherein the film lid comprises a laminated film material that includes a lower film layer made of a first plastics material for sealed attachment to the upper edge of the peripheral wall and an upper film layer made of a second plastics material that is attached by a peelable layer to the lower film layer so that it can be separated by peeling from the lower film layer, said upper film layer carrying at least one printed layer and said lower film layer being unprinted, wherein the first plastics material comprises a heat resistant plastics material, and the peelable layer is attached more strongly to the upper film layer than to the lower film layer so that it is removed entirely from the lower film layer when the upper film layer is separated by peeling from the lower film layer.
 26. A packaging container according to claim 25, wherein the peelable layer comprises a pressure sensitive adhesive.
 27. A packaging container according to claim 25, wherein the first plastics material comprises a heat resistant plastics material that can tolerate a temperature of about 130°-210° C.
 28. A packaging container according to claim 25, wherein the peelable layer has a bond strength with the lower film layer in the range 20-90 g per 25 mm width.
 29. A packaging container according to claim 25, wherein the lower film layer comprises a PET homopolymer material.
 30. A packaging container according to claim 25, wherein the lower film layer includes an upper surface layer comprising a heat sealable copolymer material.
 31. A packaging container according to claim 25, wherein the lower film layer is heat sealed to the upper edge of the peripheral wall.
 32. A packaging container according to claim 25, wherein a lower surface of the lower film layer is corona treated.
 33. A packaging container according to claim 25, wherein the upper film layer comprises a polyester material.
 34. A packaging container according to claim 25, wherein a lower surface of the upper film layer is acrylic treated.
 35. A packaging container according to claim 25, wherein the upper film layer has a thickness in the range 20-30 μm.
 36. A packaging container according to claim 25, wherein the upper film layer carries a first printed layer that can be viewed from a first side of the upper film layer and a second printed layer that can be viewed from a second side of the upper film layer.
 37. A packaging container according to claim 36, wherein the first printed layer is printed on the first side of the upper film layer and the second printed layer is printed on the second side of the upper film layer.
 38. A packaging container according to claim 36, wherein the upper film layer is transparent and the first and second printed layers are printed on the same side of the upper film layer, whereby one of the printed layers can be viewed through the transparent film from one side of the upper film layer, and the other printed layer can be viewed from the other side of the upper film layer.
 39. A packaging container according to claim 38, wherein one of the printed layers is overprinted with the other printed layer.
 40. A packaging container according to claim 36, wherein at least one printed layer is substantially opaque.
 41. A packaging container according to claim 25, wherein the lower film layer is substantially transparent.
 42. A packaging container according to claim 25, wherein the tray comprises a plastics material.
 43. A packaged food product comprising a packaging container and a food product sealed within the container, said packaging container being configured to allow heating of the food product in the packaging container and comprising a tray for receiving a food product, the tray having a base and a peripheral wall, and a film lid for sealed attachment to an upper edge of the peripheral wall to seal a food product within the container, wherein the film lid comprises a laminated film material that includes a lower film layer made of a first plastics material for sealed attachment to the upper edge of the peripheral wall and an upper film layer made of a second plastics material that is attached by a peelable layer to the lower film layer so that it can be separated by peeling from the lower film layer, said upper film layer carrying at least one printed layer and said lower film layer being unprinted, wherein the first plastics material comprises a heat resistant plastics material, and the peelable layer is attached more strongly to the upper film layer than to the lower film layer so that it is removed entirely from the lower film layer when the upper film layer is separated by peeling from the lower film layer.
 44. A packaged food product according to claim 43, wherein the food product is a pre-prepared food product, preferably a chilled or frozen food product or an ambient food product, which is intended to be heated to a serving temperature in the packaging container.
 45. A laminated film material for sealing a packaging container for a food product that is configured to allow heating of the food product in the packaging container, wherein the laminated film material includes a lower film layer made of a first plastics material for sealed attachment to the packaging container and an upper film layer made of a second plastics material that is attached by a layer of peelable adhesive to the lower film layer so that it can be separated by peeling from the lower film layer, said upper film layer carrying at least one printed layer and said lower film layer being unprinted, wherein the first plastics material comprises a heat resistant plastics material, and the peelable layer is attached more strongly to the upper film layer than to the lower film layer so that it is removed entirely from the lower film layer when the upper film layer is separated by peeling from the lower film layer. 